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I bet the crossovers mounted outside the box improves the performance a bit by cutting down vibration.

I've been thinking about this comment, and I can't imagine how vibration would have any effect on resistors or capacitors. But it does seem that physical movement of an air-coil inductor through its own magnetic field would induce a distortion. I wonder if it would be measurable or audible.

Originally Posted by boputnam

I have not experienced the dip you described, and my networks are stock - so wiring is easy the OEM way.

Interesting. I assume you are biamping? 4th order network?

I'm suspicious that with your gorgeous networks and JBL's inverted polarity there is some unintended wiring snafu.

Yes, that is very possible! Eventually I'll pull the woofer and check everything, but right now I'd rather just listen to them.

Yeah, per my pm a few weeks back. Bryston 10B LR, custom, using for the 4345 crossover point but 4th-order slope. It really tightened-up the low-end. The 2245 is such a wonderfully tonal, low Q woofer, it's nice to leave it on it's own as much as possible.

Yeah, per my pm a few weeks back. Bryston 10B LR, custom, using for the 4345 crossover point but 4th-order slope. It really tightened-up the low-end. The 2245 is such a wonderfully tonal, low Q woofer, it's nice to leave it on it's own as much as possible.

Cool. I wasn't sure if that was just a suggestion or something that you are using yourself as well. I think this will be my next project, the amplifier can wait.

The 4345's are pretty much done, but I've been keeping myself busy working on this active crossover. It's coming along nicely, all that's really left is to drill the mounting holes in the chassis.

The design is pretty simple, pretty much straight out of Douglas Self's "The Design of Active Crossovers". I did the circuit / board design myself and I had the boards printed by BatchPCB. I'm working on a discrete version, but of course that is a much bigger project and who knows when it will be done.

My goodness, that x-over looks lovely! I have a set of similar 4th order opamp pcb's on the shelf - need to solder them up too. In the long run my aim is also to end up with a discrete design x-over.
Do you have any knowledge of an existing diy kit or at least some online documentation of a completed project? Designing one is out of my leauge. I know brystons are fully discrete, and Pass too, but buying a xover thats more expensive than my amps would be a bit of a misalliance. Anyway If you end up finishing the discrete design I'm sure you'd find many LH members interested as well as other loudspeaker diy nuts to be found on boards across the world.

The meat of the discrete project is designing an opamp. I was thinking it would be cool to design it so that the whole board can plug into a standard DIP8 opamp socket, using the same pinout as the 5532. Then I will upgrade the opamps in my cd player, receiver, equalizer, and so on, and I'll have a fully discrete signal chain without spending kilobucks. And it sounds like just what you're looking for, as an upgrade for your opamp crossover kit.

But I'm not going to make any promises until I at least have a working prototype

The meat of the discrete project is designing an opamp. I was thinking it would be cool to design it so that the whole board can plug into a standard DIP8 opamp socket, using the same pinout as the 5532. Then I will upgrade the opamps in my cd player, receiver, equalizer, and so on, and I'll have a fully discrete signal chain without spending kilobucks. And it sounds like just what you're looking for, as an upgrade for your opamp crossover kit.

But I'm not going to make any promises until I at least have a working prototype

It is a noticeable upgrade from the m552. Midbass is more defined, bass and drums are sharper and clearer. Also there seems to be a bit more resolution in the highs.

It went together pretty much as planned. I messed up the gain structure, and I'm stuck with +6dB gain - I can fix it, but I'll have to order more parts. Also there was a defect in one of the PCB's copper layers, causing a short between traces. It was frustrating to track down - next time I need to inspect the boards more thoroughly before assembly.

So what's next? The discrete op-amp, power amps, or maybe back to the wood shop for a matching birch rack / tv table.